How can you tell if roof shingles contain asbestos?
Short answer. You cannot confirm asbestos by looking; only a lab test of a sample can, but rigid, flat, cement-like shingles on a house built before about 1980 are a strong clue, especially if they are gray, brittle and laid in a diamond or rectangular pattern. If you suspect asbestos, do not cut, break or pressure wash the shingles; have a qualified professional sample them, and use a licensed abatement contractor if removal is needed.
Visual clues
- Material: asbestos cement shingles are hard and stiff, like thin concrete, not flexible like asphalt.
- Shape: often square, rectangular or diamond-shaped, sometimes with a textured or wood-grain surface.
- Color: gray, white, green or red, often faded.
- Age: mostly on homes and outbuildings built from the early 1900s to around 1980.
- Layers: sometimes a later layer of asphalt shingles was installed right over them.
Some older asphalt shingles and roofing felts also contained asbestos, and those are impossible to spot by eye.
Why it matters
Intact asbestos cement shingles are relatively stable. The risk comes from breaking, cutting, sanding or pressure washing them, which can release fibers. Tear-off, repairs and even walking on brittle shingles can break them.
What to do
- Leave them alone until they are tested.
- Have a qualified asbestos inspector take a sample and send it to an accredited lab.
- If it is positive, ask about the options: leaving them in place, encapsulation or professional removal.
- Check with your local building department and the Georgia Environmental Protection Division on removal and disposal rules.
Roofing over them
Some owners roof over asbestos cement shingles to avoid removal. Whether that is allowed depends on the code, the condition of the existing roof and the new product's requirements. See roofing over existing shingles and signs you need a new roof.